A belt in the 1640s was not worn to keep your breeches up. Generally if you had a pair that fitted, you didn’t need a belt, but as has been shown previously the standard fixing if you needed it was hooks and eyes, the hooks on your breeches attaching to the eyes on your coat or doublet. Braces are not known in our period either, the earliest surviving set are in Stockholm and date to 1650. The pedlar on the left in the woodcut has a belt around his waist and another to keep his pack on his shoulders.
Belts were worn over the coat, around the waist and were used to carry keys or purses for example, but could also carry a hanger for a sword. They were also worn with the better kind of doublet, often covered with the same fabric and fitted to the waistline. This fashion was dying out in the 1640s as the pointed waistline softened but would have been in evidence in the country and on less fashionable suits. Hooks or loops were sewn on top of the doublet with metal fittings to take a sword hanger.
The particular characteristic of 17th century belts is that they are narrow, usually no more that ¾” wide and the buckle is generally of the double loop or spectacle type with a keeper. There are no wide belts of the kind favoured in pirate films in evidence either in museums or images. Two particularly fine examples below are made by Karl Robinson.
Belt bags were worn by many and could be large or small. Woodcuts show rustic countrymen and pedlars with what we’d call a man bag in the 21st century. The image below is another Karl Robinson production and has several compartments to keep your necessities in.